Warning valve

ABSTRACT

A warning valve having particular use in breathing apparatus comprising a chamber with a moveable valve body adapted to cooperate with a main valve seat in a feed line communicating with the chamber, characterized in that the feed line is connected to the chamber via on the one hand a main duct and on the other hand a bypass duct, the valve body being arranged so that in a first step it closes the main duct and in a second step it also closes the bypass duct.

United States Patent Sandstrom 1 Jan. 29, 1974 WARNING VALVE 3,387,623 6/1968 Essig 137/5162? x [75] Inventor: Jan Erik Stellan Sandstrom,

Djursholm, Sweden Primary ExaminerRobert G. Nilson [73] AsslgneeZ AGA Aktlebolag Sweden Attorney, Agent, or FirmLarson, Taylor & Hinds [22] Filed: Aug. 7, 1972 Appl. No.: 278,186

Related US. Application Data Continuation of Ser. No. 94,769, Dec. 3, 1970, abandoned.

US. Cl l28/l42.3, 137/110, 137/516.13, 137/5l6.27, 137/DIG. 9

Int. Cl A62b 9/02 Field of Search...137/63 R, 110, 512.1, 513.3, 137/516] 1, 516.13, 516.27; 128/142, 142.2, 142.3

References Cited UNITED STATES PATENTS 9/1964 Lecocq 128/1423 UX ABSTRACT A warning valve having particular use in breathing apparatus comprising a chamber with a moveable valve body adapted to cooperate with a main valve seat in a feed line communicating with the chamber, characterized in that the feed line is connected to the chamber via on the one hand a main duct and on the other hand a bypass duct, the valve body being arranged so that in a first step it closes the main duct and in a second step it also closes the bypass duct.

6 Claims, 3 Drawing Figures PATENTED JAN 2 9 I974 INVENTOR JAN ERIK STELLAN SANDSTRGM ATTORNEYS A $501 Ja7/ WARNING VALVE This is a continuation, of application Ser. No. 94,769 filed Dec. 3, 1970, now abandoned.

The present invention relates to a warning valve having particular use in breathing apparatus.

In the use of self-contained breathing apparatus as, for instance, in smoke jumping and in water diving operations it is necessary for the user of such apparatus to be forwarned when the oxygen-containing gas supply he is carrying begins to give out in sufficient time to enable him to return to his starting point before the gas supply is empty. This warning can take place either through the gas supply stopping completely or gradually. The diver is then forced to open with a single movement a reserve air valve so as to obtain again an essential supply of gas. Neither of these methods of forewarning the user of the breathing apparatus has proved entirely satisfactory, however. The method which involves the gradual stoppage of the gas supply has been criticized as being physiologically unsuitable, while the complete stoppage method has been found to be disagreable to the user.

Another warning valve which has been proposed gives a forewarning in such a manner that the diver at a certain pre-specified or predetermined primary pressure P, will have the gas supply cut off at the end of each breathing-in during a short period of time before the gas supply stops completely at a primary pressure P in the gas supply. This known valve has proved to be extremely uncertain, and to make it operate at all, it is essential that great pains be taken during its manufacture to ensure the valve exhibits a high measuring accuracy.

It is an object of this invention, therefore, to provide a warning valve characterized by its safety and ease of manufacture which overcomes the shortcomings of the prior warning methods and valves. This and other objects of the invention can be obtained by a warning valve which comprises a valve chamber, a moveable valve body in said valve chamber, an outlet means communicating with said chamber, a feed inlet means, a moveable element in said feed inlet means having a passageway therethrough to provide communication between said feed inlet means and said chamber, said moveable element projecting inside said chamber wherein the valve is in open position (be it a partially or fully open position), the surface of the moveable element projecting into said chamber and facing said valve body forming an initial valve seat which said valve body encounters at a predetermined or pre-specified first drop in pressure in said gas supply to close off gas flow from the entrance of said passageway directly into said chamber, a bypass means communicating between the passageway in the feed inlet means and the chamber when the valve body encounters the initial valve seat and a main valve seat provided the feed inlet means which the valve body encounters upon a further drop in pressure in the chamber to close off the bypass means.

The bypass means of the invention according to one embodiment of the invention takes the form of a nozzle arranged in the wall of the moveable element projecting into the chamber. Alternatively, the bypass means may take the form of a duct built into the valve body, which duct is of smaller diameter than the passageway in the moveable element. In this embodiment the bying facing the main valve body. In yet another embodiment the bypass means comprises a duct in the valve seat opening at one end into the feed inlet means and at the other end into the chamber and an opening in the moveable element aligned with said duct opening into said feed inlet means to provide communication between the duct and the passageway in the moveable element, the duct opening into the chamber facing the valve body.

The invention will be further described with reference to the accompanying drawing wherein:

FIG. 1 is a schematic cross-sectional view of a preferred embodiment of the valve of the invention in fully open position;

FIG. 2 is a portion of FIG. 1 showing another embodiment of the valve of the invention wherein the bypass means is built into the valve body;

FIG. 3 is a portion of FIG. 1 but showing yet another embodiment of the valve of the invention wherein the bypass means ends in the valve seat.

Referring to FIG. 1, the warning valve has a chamber 1, in which can move a valve body 2 biassed by a spring 3. The chamber 1 is provided, moreover, with a feed inlet means such as a feed line 4 and a feed outlet means such as feed outlet line 5. Around the opening of the feed line 4 is provided a main valve seat 6 and inside the feed line 4 is inserted a movable element, preferably a piece of pipe 8. The piece of pipe 8 comprises a main passageway or duct 7, which at its orifice in the chamber 1 forms a valve seat 9. The piece of pipe also has a bypass means such as a bypass line 10 of smaller diameter than the main passageway or duct 7, provided in the close vicinity of its valve seat 9. In the position shown in the drawing the warning valve is fully open and the piece of pipe 8 is held by the spring 11 in a position projecting into the chamber 1. The feed line 4 communicates with a pressure gas contained shown diagrammatically as box 13 and the outlet line 5 is connected via a pressure controller to a breathing mask shown diagrammatically as box 15.

When the pressure in the pressure gas container drops to a certain first pre-determined or pre-specific primary pressure P the corresponding pressure in chamber 1 is unable to hold back valve body 2 which is then spring-urged to drop down towards the initial valve seat 9 of the piece of pipe 8, finally seating and closing off the main passageway or duct 7. At this stage a bypass flow is obtained through the nozzle 10, the amount of flow depending on the pressure P and on the diameter of the nozzle 10. When the pressure P in the pressure gas container and the corresponding pressure in chamber 1 drops further the valve body continues to move downward towards the outer fixed seat 6 until it contacts the main valve seat 6 thereby also closing off the bypass flow.

Referring to FIG. 2 the bypass means is in the form of a duct 10 (a) built into the head of the valve body 2 and is of a smaller diameter than the diameter of the passageway 7. The duct 10 (a) is arranged so that its opening at one end is in alignment with passageway 7 and the opening of the other end faces main valve seat 6. In this embodiment, upon the first drop in pressure in the chamber 1 the valve body 2 drops into the valve seat 9 thereby closing off gas flow from the passageway 7 directly into the chamber. At this position, a bypass flow is established from the passageway 7 through the narrower duct 10 (a) in valve body into the chamber. Seating of the valve body onto main valve seat 6 upon a further drop in pressure in the chamber 1 then closes off the bypass flow.

Referring to FIG. 3, the bypass means in this embodiment is a duct 10 (b) built into the valve seat so taht one end opens into the chamber 1 facing valve body 2 and the other end opens into feed line 4 at a point facing the valve body 2. An opening 10 (c) is provided the side wall of the moveable element 8 in alignment with the end of duct 19 (b) opening into the feed line. The first drop in pressure in the chamber 1 drops the valve body 2 onto the initial valve seat 9 establishing bypass flow via ducts 10 (b) and 10 into chamber 1. The seating of valve body 2 on main valve seat 6 upon a further drop in pressure in chamber 1 closes off the bypass flow.

It is Claimed:

l. A breathing apparatus comprising in combination, a breathing mask, a pressure gas container means and a warning valve, said warning valve comprising:

a an enclosed valve chamber;

b an outlet means communicating at one end with said chamber and at the other end with said breathing mask;

c a feed inlet means communicating at one end with said chamber and at the other end with said pressure gas container means;

d a moveable valve body in said valve chamber responsive to a drop in pressure in said valve chamber;

e said valve body being located in said enclosed chamber in a manner that provides upon said drop in pressure in said chamber movement of said valve body in a direction opposite the gas flow into said chamber;

f a moveable element in said feed inlet means having a passageway therethrough to provide communication between said feed inlet means and said chamber, said moveable element projecting inside said chamber when the valve is in open position;

g the surface of said moveable element projecting into said chamber and facing said valve body forming an initial valve seat which said valve body encounters at a predetermined first drop in pressure in said chamber to close off gas flow from the entrance of the passage-way directly into said chamber;

h bypass means for providing communication between the passageway in said moveable element and said chamber when said valve body encounters said initial valve seat;

i a main valve seat provided in said feed inlet means which the valve body encounters upon a further drop in pressure in said chamber to close off said bypass means.

2. A breathing apparatus according to claim 1 wherein the valve body is spring-biassed.

3. A breathing apparatus according to claim 2 wherein the bypass means has the form of a nozzle arranged in the wall of the moveable element.

4. A breathing apparatus according to claim 1 wherein the moveable element has the form of a pipe.

5. A breathing apparatus according to claim 4 wherein the moveable element is spring-loaded.

6. A breathing apparatus according to claim 1 wherein the bypass means is a duct located in said valve body, said duct being of smaller diameter than the passageway in said moveable element and extending from an opening in alignment with said passageway to an opening facing the main valve seat. 

1. A breathing apparatus comprising in combination, a breathing mask, a pressure gas container means and a warning valve, said warning valve comprising: a an enclosed valve chamber; b an outlet means communicating at one end with said chamber and at the other end with said breathing mask; c a feed inlet means communicating at one end with said chamber and at the other end with said pressure gas container means; d a moveable valve body in said valve chamber responsive to a drop in pressure in said valve chamber; e said valve body being located in said enclosed chamber in a manner that provides upon said drop in pressure in said chamber movement of said valve body in a direction opposite the gas flow into said chamber; f a moveable element in said feed inlet means having a passageway therethrough to provide communication between said feed inlet means and said chamber, said moveable element projecting inside said chamber when the valve is in open position; g the surface of said moveable element projecting into said chamber and facing said valve body forming an initial valve seat which said valve body encounters at a predetermined first drop in pressure in said chamber to close off gas flow from the entrance of the passage-way directly into said chamber; h bypass means for providing communication between the passageway in said moveable element and said chamber when said valve body encounters said initial valve seat; i a main valve seat provided in said feed inlet means which the valve body encounters upon a further drop in pressure in said chamber to close off said bypass means.
 2. A breathing apparatus according to claim 1 wherein the valve body is spring-biassed.
 3. A breathing apparatus according to claim 2 wherein the bypass means has the form of a nozzle arranged in the wall of the moveable element.
 4. A breathing apparatus according to claim 1 wherein the moveable element has the form of a pipe.
 5. A breathing apparatus according to claim 4 wherein the moveable element is spring-loaded.
 6. A breathing apparatus according to claim 1 wherein the bypass means is a duct located in said valve body, said duct being of smaller diameter than the passageway in said moveable element and extending from an opening in alignment with said passageway to an opening facing the main valve seat. 